Ratchet based control device of large-sized parasol

ABSTRACT

A parasol control device includes a shaft rotatably received in aligned holes defined in a central rod of the parasol. A handle is coupled to a first end of the shaft for manually rotating the shaft. A rope is fastened to the shaft whereby when the shaft is rotated, the rope is wound to/unwound from the shaft for opening/closing the parasol. A ratchet wheel defines a central bore tightly fit over the shaft whereby a friction is present between the ratchet wheel and the shaft. A block is attached to the rod and defines a bore for rotatably supporting the shaft. A blind hole is defined in the block with a spring biased pin received in the blind hole. A free end of the pin engages with the teeth of the ratchet for generating consecutive impact sounds when the shaft is rotated in a first direction to open the parasol. When the shaft is rotated in an opposite second direction to close the parasol, the ratchet wheel is prevented from rotation by the pin. With a sufficient large torque applied to the shaft, the friction is overcome and the shaft is rotated in the second direction to release the rope for closing the parasol.

FIELD OF THE INVENTION

[0001] The present invention generally relates to a large-sized parasol,such as a beach parasol and a garden parasol, and in particular to aratchet based control mechanism for opening/closing the large-sizedparasol.

BACKGROUND OF THE INVENTION

[0002] Large-sized umbrellas or parasols, such as garden parasols andbeach parasols, are usually equipped with a handle or handwheel foroperating a rope-based driving mechanism to open/close a canopy of theparasol. The large-sized parasol usually comprises a central rod alongwhich a runner is movably mounted. A crown is attached to a top end ofthe central rod. Ribs extend from the crown for supporting the canopy.Stretchers extend from the runner and pivoted to the ribs whereby bymoving the runner along the central rod, the ribs are caused to movetoward/away from the central rod and thus opening/closing the canopy. Arope that is manually wound/unwound by means of the handle has an endattached to the runner whereby winding/unwinding the rope moves therunner along the central rod.

[0003] For the large-sized parasols, the torque required to rotate thehandle is quite large, causing manual operation thereof to be difficult.A disadvantage is that during the process of winding the rope to openthe canopy, an operator must from time to time maintain the requiredtorque to ensure smooth opening of the parasol. Devices for temporarilyretaining the rope during the winding process are available in themarket. Such devices allow an operator to be temporarily released frommaintaining the required torque by himself or herself. However, suchdevices are very complicated and thus expensive. In addition, suchdevices are not able to provide a stepwise operation which ensuresproper progress of winding the rope by the operator.

[0004] It is thus desirable to provide a large-sized parasol having astepwise control device for winding/unwinding a rope thereof in order toovercome the above discussed problems.

SUMMARY OF THE INVENTION

[0005] Accordingly, an object of the present invention is to provide acontrol device for opening/closing a large-sized parasol, the devicecomprising a ratchet based mechanism consisting of a ratchet wheel and apin cooperating with ratchet wheel to control the opening/closingoperation in a stepwise fashion.

[0006] Another object of the present invention is to provide a controldevice for a large-sized parasol comprising a mechanism for generatingconsecutive impact sounds during opening the parasol for indication ofproper operation.

[0007] A further object of the present invention is to provide a controlmechanism for opening/closing a large-sized parasol, the controlmechanism having a simple structure and thus low costs.

[0008] To achieve the above objects, in accordance with the presentinvention, there is provided a parasol control mechanism comprising ashaft rotatably received in aligned holes defined in a central rod ofthe parasol. A handle is coupled to a first end of the shaft formanually rotating the shaft. A rope is fastened to the shaft wherebywhen the shaft is rotated, the rope is wound to/unwound from the shaftfor opening/closing the parasol. A ratchet wheel defines a central boretightly fit over the shaft whereby a friction is present between theratchet wheel and the shaft. A block is attached to the rod and definesa bore for rotatably supporting the shaft. A blind hole is defined inthe block with a spring biased pin received in the blind hole. A freeend of the pin engages with the teeth of the ratchet for generatingconsecutive impact sounds when the shaft is rotated in a first directionto open the parasol. When the shaft is rotated in an opposite seconddirection to close the parasol, the ratchet wheel is prevented fromrotation by the pin. With a sufficient large torque applied to theshaft, the friction is overcome and the shaft is rotated in the seconddirection to release the rope for closing the parasol.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be apparent to those skilled in theart by reading the following description of preferred embodimentsthereof, with reference to the attached drawings, in which:

[0010]FIG. 1 is a schematic side elevational view of a large-sizedparasol constructed in accordance with the present invention with acanopy removed for simplification purposes;

[0011]FIG. 2 is a cross-sectional view of a portion of the large-sizedparasol of the present invention showing a stepwise control device inaccordance with a preferred embodiment of the present invention;

[0012]FIG. 3 is an exploded view of FIG. 2; and

[0013]FIG. 4 is similar to FIG. 3 but showing another embodiment of thestepwise control device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] With reference to the drawings and in particular to FIG. 1, aparasol constructed in accordance with the present invention comprisesan elongated, upright, tubular central rod 11 having a lower end mountedto a base (not labeled) and an upper end to which a crown (not shown) inmounted. A plurality of ribs (not labeled) is pivotally mounted to andradially extends from the crown. A runner 14 is movably mounted to thecentral rod 11 to be movable toward/away from the crown. A stretcher 15is pivotally mounted between each rib and the runner 14. A rope 13 has amajor portion received in and extending along the central rod 11 with anend portion extending out of the rod 11 and attached to the runner 14whereby by pulling/releasing the rope 13, the runner 14 is driven alongthe rod 11 to open/close the parasol.

[0015] Also referring to FIGS. 2 and 3, a stepwise control device 10 ismounted to the rod 11 and coupled to the rope 13 for pulling/releasingthe rope 13. The control device 10 comprises a shaft 20 extending, in alateral direction with respect to the rod 12, through and rotatablysupported by aligned holes 17 defined in the rod 11. The shaft 20 has afirst end 27 that is expanded. A driving section 21 having a squarecross section is formed next to the expanded end 27. A cylindricalsection 22 extends from the driving section 21 to a second end 26 of theshaft 17. Threading is formed on the second end 26. A circumferentialgroove 24 having a semi-circular cross section is formed in thecylindrical section 22 with a hole 23 defined in the groove 24. Theshaft 20 forms a retaining section 25 next to the threaded second end26.

[0016] A handle 12 has an end defining a square hole (not labeled)snugly fit over and retained by the driving section 21 of the shaft 20whereby a driving coupling is formed between the handle 12 and the shaft20. The shaft 20 can thus be rotated by the handle 12. The handle 12 iskept in position by the expanded end 27 of the shaft 20. A spring 40surrounds the cylindrical section 22 of the shaft 20 with ends engagingthe rod 11 and the shaft 20. In the embodiment illustrated, a washer 41is fit on the shaft 20 interposed between the spring 40 and aninward-extending portion (not labeled) of the handle 12 for biasing theshaft 20 and the handle 12 with respect to the rod 11.

[0017] Two blocks 30 are disposed on opposite sides of the rod 11corresponding to the holes 17. Each block 30 forms an inward projection32 snugly received in the corresponding hole 17. A bore (not labeled) isdefined in the projection 32 of each block 30 for receiving androtatably supporting the shaft 20. Each block 30 forms a raised section(not labeled) forming a shoulder 33. A blind hole 34 is defined in theraised section and exposed to the surface of the shoulder 33. A pin 36is received in the blind hole 34 and biased by a spring 35 to have afree end of the in 36 projecting out of the blind hole 34. Preferably,each block 30 has a curved surface 31 conforming with the rod 11.

[0018] A ratchet wheel 50 defines a central bore 53 fit over andretained in the retaining section 25 of the shaft 20 whereby the pin 36,serving as a ratchet, engages teeth 54 of the ratchet wheel 50.Preferably two washers 51 are arranged on both sides of the ratchetwheel 50. The bore 53 is dimensioned so that the ratchet wheel 50 istightly fit over the retaining section 25 with a predetermined amount offriction present between the retaining section 25 and the bore 53whereby the ratchet wheel 50 is rotatable in unison with the shaft 20.However, when a sufficient amount of resistance that is greater than thefriction, is applied to the ratchet wheel 50 during the rotation of theshaft 20, the shaft 20 is allowed to rotate with respect to the ratchetwheel 50. A nut 52 engages the threaded end 26 of the shaft 20 forsecuring the ratchet wheel 50 on the shaft 20 and causing compression ofthe spring 40. The biasing force of spring 40 secures the blocks 30 andratchet wheel 50 in position.

[0019] If desired, a casing 16 is provided to house the control device10.

[0020] The rope 13 has an inner end portion fastened to the shaft 20through the hole 23 whereby when the shaft 20 is rotated, the rope 13 iswound to and/or unwound from the cylindrical section 22 of the shaft 20for moving the runner 14 to open and/or close the parasol.

[0021] To open the parasol, a user rotates the shaft 20 in a firstdirection via the handle 12 to wind the rope 13 to the shaft 20. In theopening operation, the ratchet wheel 50 is rotated with the shaft 20 dueto the friction therebetween. When the ratchet wheel 50 rotates, thefree end of the pin 36 that is biased by the spring 35 hits the teeth 54one by one and consecutively, causing successive impact sounds toindicate the operation of the control device 10. When the user releasesthe handle 12, due to gravity, the parasol intends to close itself,causing the shaft 20 to rotate in an opposite second direction. Such arotation in the second direction is stopped by the engagement betweenthe pin 36 and the teeth 54 of the ratchet wheel 50. This allows theuser to open the parasol to any desired extent and keeps the parasol atsuch an open condition.

[0022] To close the parasol, the user forcibly rotate the shaft 20 inthe second direction so as to overcome the friction between the ratchetwheel 50 and the shaft 20 whereby the shaft 20 is allowed to rotate withrespect to the ratchet wheel 50. The rope 13 is thus allowed to unwindfrom the shaft 20 without being confined by the engagement between thepin 36 and the ratchet wheel 50.

[0023]FIG. 4 shows another embodiment of the present invention which issubstantially identical to the embodiment shown in FIGS. 2 and 3. Tosimplify the description and illustration, elements of FIG. 4 having thesame function as those of FIGS. 2 and 3 bear the same referencenumerals. In the embodiment of FIG. 4, the blocks 30 are arranged insuch a way that the pin 36 that is movably received in the blind hole 34of the block 30 is allowed to slide off the blind hole 34 by means ofgravity. In other words, the blind hole 34 is arranged in a verticallydownward direction whereby the pin 36 may be caused by the gravity toslide off the hole 34. The pin 36 has a lower free end (not labeled)engaging the teeth 54 of the ratchet 50 for performing the same functionof the pin 36 of FIGS. 2 and 3. The remaining description of theembodiment of FIG. 4 is substantially the same as that of the embodimentof FIGS. 2 and 3. Thus, no further detail is needed herein.

[0024] Although the present invention has been described with referenceto the preferred embodiments thereof, it is apparent to those skilled inthe art that a variety of modifications and changes may be made withoutdeparting from the scope of the present invention which is intended tobe defined by the appended claims.

What is claimed is:
 1. A control device adapted to be mounted alongitudinally extending rod of a parasol for pulling/releasing a ropeextending along the rod to open/close the parasol a shaft extending in alateral direction through the rod and rotatably supported thereby, ahole being defined in the shaft for fastening the rope to the shaftwhereby rotation of the shaft causes the rope to be wound to/unwoundfrom the shaft for opening/closing the parasol; a ratchet wheel fit overa retaining section of the shaft whereby when the shaft is rotated in afirst direction, the ratchet wheel is rotated in unison therewith; and apin resiliently biased to engage teeth of the ratchet for allowing theratchet wheel to rotate in the first direction while preventing theratchet wheel from rotation in a second direction opposite to the firstdirection.
 2. The control device as claimed in claim 1, wherein theshaft comprises a driving section having a square cross section overwhich a square hole of a handle is fit whereby the shaft is drivinglycoupled to the handle.
 3. The control device as claimed in claim 2,wherein the shaft has an expanded end for retaining the handle and athreaded end with which a nut engages, a spring being arranged betweenthe expanded end of the shaft and the rod of the parasol for biasing theshaft and cooperation with the nut to retain the handle and the ratchetwheel in position.
 4. The control device as claimed in claim 1 furthercomprising a block having a surface conforming with the rod and aprojection extending from the surface into a hole defined in the rod, abore being defined in the projection for rotatably supporting the shaft,a blind hole being defined in the block for receiving the pin therein, abasing element being arranged between the pin and the blind hole forbiasing a free end of the pin to engage the teeth of the ratchet wheel.5. The control device as claimed in claim 1 further comprising a blockhaving a surface conforming the rod and a projection extending from thesurface into a hole defined in the rod, a bore being defined in theprojection for rotatably supporting the shaft, a hole being defined inthe block for movably receiving the pin with the pin being so orientedthat the pin is driven by gravity to have a free end thereof engagingthe teeth of the ratchet wheel.
 6. The control device as claimed inclaim 1, wherein the ratchet wheel defines a central bore having adimension for tightly engaging the retaining section of the shaftwhereby a friction is present between the ratchet wheel and theretaining section, the friction being large enough to ensure rotation ofthe ratchet wheel with the shaft in the first direction.
 7. The controldevice as claimed in claim 6, wherein the friction is small enough toallow the shaft to be rotatable with respect to the ratchet when theshaft is rotated in the second direction with the ratchet wheel beingprevented from rotation by the pin.